The term juvenile ossifying fibroma is used in the literature in naming 2 microscopically distinct fibro-osseous lesions of the craniofacial skeleton. One is characterized by small uniform spherical ossicles resembling psammoma bodies (psammomatoid juvenile ossifying fibroma). The other is distinguished by trabeculae of fibrillary osteoid and woven bone (trabecular juvenile ossifying fibroma). Three new cases of each type are reported, and the literature is extensively reviewed for published cases of these 2 entities.Psammomatoid juvenile ossifying fibroma is reported more commonly than trabecular juvenile ossifying fibroma. It affects patients from a wider age range (3 months to 72 years) and an older mean age range (16-33 years) as compared with 2 to 12 years and 8(1/2) to 12 years, respectively, for trabecular juvenile ossifying fibroma. In both types there is a slight male predominance and the lesions are unencapsulated and tend to infiltrate adjacent bone. A significant difference between the 2 tumors is their site of occurrence. Although psammomatoid juvenile ossifying fibroma occurs predominantly in the sinonasal and orbital bones, trabecular juvenile ossifying fibroma predominantly affects the jaws. Aggressive growth occurs in some-but not all-cases of both types. Such behavior may be related to younger patient age and the concurrent development of aneurysmal bone cysts, which is seen more frequently in psammomatoid juvenile ossifying fibroma. This study demonstrates that not only histologic but also demographic and clinical differences between psammomatoid juvenile ossifying fibroma and trabecular juvenile ossifying fibroma warrant their classification as 2 distinct clinicopathologic entities.